Merge branch 'work.sendfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull sendfile updates from Al Viro:
 "Make sendfile() to pipe destination do the right thing, should make
  'fs/pipe: allow sendfile() to pipe again' redundant"

* 'work.sendfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  teach sendfile(2) to handle send-to-pipe directly
  take the guts of file-to-pipe splice into a helper function
  do_splice_to(): move the logics for limiting the read length in

fs/internal.h

@@ -15,6 +15,7 @@ struct mount;
 struct shrink_control;
 struct fs_context;
 struct user_namespace;
+struct pipe_inode_info;
 
 /*
  * block_dev.c
@@ -193,3 +194,11 @@ int sb_init_dio_done_wq(struct super_block *sb);
  */
 int do_statx(int dfd, const char __user *filename, unsigned flags,
 	     unsigned int mask, struct statx __user *buffer);
+
+/*
+ * fs/splice.c:
+ */
+long splice_file_to_pipe(struct file *in,
+			 struct pipe_inode_info *opipe,
+			 loff_t *offset,
+			 size_t len, unsigned int flags);

fs/read_write.c

@@ -1188,6 +1188,7 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 {
 	struct fd in, out;
 	struct inode *in_inode, *out_inode;
+	struct pipe_inode_info *opipe;
 	loff_t pos;
 	loff_t out_pos;
 	ssize_t retval;
@@ -1228,9 +1229,6 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 	in_inode = file_inode(in.file);
 	out_inode = file_inode(out.file);
 	out_pos = out.file->f_pos;
-	retval = rw_verify_area(WRITE, out.file, &out_pos, count);
-	if (retval < 0)
-		goto fput_out;
 
 	if (!max)
 		max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
@@ -1253,9 +1251,18 @@ static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
 	if (in.file->f_flags & O_NONBLOCK)
 		fl = SPLICE_F_NONBLOCK;
 #endif
-	file_start_write(out.file);
-	retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
-	file_end_write(out.file);
+	opipe = get_pipe_info(out.file, true);
+	if (!opipe) {
+		retval = rw_verify_area(WRITE, out.file, &out_pos, count);
+		if (retval < 0)
+			goto fput_out;
+		file_start_write(out.file);
+		retval = do_splice_direct(in.file, &pos, out.file, &out_pos,
+					  count, fl);
+		file_end_write(out.file);
+	} else {
+		retval = splice_file_to_pipe(in.file, opipe, &pos, count, fl);
+	}
 
 	if (retval > 0) {
 		add_rchar(current, retval);

fs/splice.c

@@ -771,11 +771,16 @@ static long do_splice_to(struct file *in, loff_t *ppos,
 			 struct pipe_inode_info *pipe, size_t len,
 			 unsigned int flags)
 {
+	unsigned int p_space;
 	int ret;
 
 	if (unlikely(!(in->f_mode & FMODE_READ)))
 		return -EBADF;
 
+	/* Don't try to read more the pipe has space for. */
+	p_space = pipe->max_usage - pipe_occupancy(pipe->head, pipe->tail);
+	len = min_t(size_t, len, p_space << PAGE_SHIFT);
+
 	ret = rw_verify_area(READ, in, ppos, len);
 	if (unlikely(ret < 0))
 		return ret;
@@ -856,15 +861,10 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
 	WARN_ON_ONCE(!pipe_empty(pipe->head, pipe->tail));
 
 	while (len) {
-		unsigned int p_space;
 		size_t read_len;
 		loff_t pos = sd->pos, prev_pos = pos;
 
-		/* Don't try to read more the pipe has space for. */
-		p_space = pipe->max_usage -
-			pipe_occupancy(pipe->head, pipe->tail);
-		read_len = min_t(size_t, len, p_space << PAGE_SHIFT);
-		ret = do_splice_to(in, &pos, pipe, read_len, flags);
+		ret = do_splice_to(in, &pos, pipe, len, flags);
 		if (unlikely(ret <= 0))
 			goto out_release;
 
@@ -1002,6 +1002,23 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
 			       struct pipe_inode_info *opipe,
 			       size_t len, unsigned int flags);
 
+long splice_file_to_pipe(struct file *in,
+			 struct pipe_inode_info *opipe,
+			 loff_t *offset,
+			 size_t len, unsigned int flags)
+{
+	long ret;
+
+	pipe_lock(opipe);
+	ret = wait_for_space(opipe, flags);
+	if (!ret)
+		ret = do_splice_to(in, offset, opipe, len, flags);
+	pipe_unlock(opipe);
+	if (ret > 0)
+		wakeup_pipe_readers(opipe);
+	return ret;
+}
+
 /*
  * Determine where to splice to/from.
  */
@@ -1081,20 +1098,7 @@ long do_splice(struct file *in, loff_t *off_in, struct file *out,
 		if (out->f_flags & O_NONBLOCK)
 			flags |= SPLICE_F_NONBLOCK;
 
-		pipe_lock(opipe);
-		ret = wait_for_space(opipe, flags);
-		if (!ret) {
-			unsigned int p_space;
-
-			/* Don't try to read more the pipe has space for. */
-			p_space = opipe->max_usage - pipe_occupancy(opipe->head, opipe->tail);
-			len = min_t(size_t, len, p_space << PAGE_SHIFT);
-
-			ret = do_splice_to(in, &offset, opipe, len, flags);
-		}
-		pipe_unlock(opipe);
-		if (ret > 0)
-			wakeup_pipe_readers(opipe);
+		ret = splice_file_to_pipe(in, opipe, &offset, len, flags);
 		if (!off_in)
 			in->f_pos = offset;
 		else